Commit 54ac2c94 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

selftests/bpf: test cases for __arg_untrusted 



Check usage of __arg_untrusted parameters with PTR_TO_BTF_ID:
- combining __arg_untrusted with other tags is forbidden;
- non-kernel (program local) types for __arg_untrusted are forbidden;
- passing of {trusted, untrusted, map value, scalar value, values with
  variable offset} to untrusted is ok;
- passing of PTR_TO_BTF_ID with a different type to untrusted is ok;
- passing of untrusted to trusted is forbidden.

Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250704230354.1323244-7-eddyz87@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent aaa0e57e

tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c

+81 −0
Original line number Diff line number Diff line
@@ -179,4 +179,85 @@ int BPF_PROG(trusted_acq_rel, struct task_struct *task, u64 clone_flags) 
	return subprog_trusted_acq_rel(task);

}



__weak int subprog_untrusted_bad_tags(struct task_struct *task __arg_untrusted __arg_nullable)

{

	return task->pid;

}



SEC("tp_btf/sys_enter")

__failure

__msg("arg#0 untrusted cannot be combined with any other tags")

int untrusted_bad_tags(void *ctx)

{

	return subprog_untrusted_bad_tags(0);

}



struct local_type_wont_be_accepted {};



__weak int subprog_untrusted_bad_type(struct local_type_wont_be_accepted *p __arg_untrusted)

{

	return 0;

}



SEC("tp_btf/sys_enter")

__failure

__msg("arg#0 reference type('STRUCT local_type_wont_be_accepted') has no matches")

int untrusted_bad_type(void *ctx)

{

	return subprog_untrusted_bad_type(bpf_rdonly_cast(0, 0));

}



__weak int subprog_untrusted(const volatile struct task_struct *restrict task __arg_untrusted)

{

	return task->pid;

}



SEC("tp_btf/sys_enter")

__success

__log_level(2)

__msg("r1 = {{.*}}; {{.*}}R1_w=trusted_ptr_task_struct()")

__msg("Func#1 ('subprog_untrusted') is global and assumed valid.")

__msg("Validating subprog_untrusted() func#1...")

__msg(": R1=untrusted_ptr_task_struct")

int trusted_to_untrusted(void *ctx)

{

	return subprog_untrusted(bpf_get_current_task_btf());

}



char mem[16];

u32 off;



SEC("tp_btf/sys_enter")

__success

int anything_to_untrusted(void *ctx)

{

	/* untrusted to untrusted */

	subprog_untrusted(bpf_core_cast(0, struct task_struct));

	/* wrong type to untrusted */

	subprog_untrusted((void *)bpf_core_cast(0, struct bpf_verifier_env));

	/* map value to untrusted */

	subprog_untrusted((void *)mem);

	/* scalar to untrusted */

	subprog_untrusted(0);

	/* variable offset to untrusted (map) */

	subprog_untrusted((void *)mem + off);

	/* variable offset to untrusted (trusted) */

	subprog_untrusted((void *)bpf_get_current_task_btf() + off);

	return 0;

}



__weak int subprog_untrusted2(struct task_struct *task __arg_untrusted)

{

	return subprog_trusted_task_nullable(task);

}



SEC("tp_btf/sys_enter")

__failure

__msg("R1 type=untrusted_ptr_ expected=ptr_, trusted_ptr_, rcu_ptr_")

__msg("Caller passes invalid args into func#{{.*}} ('subprog_trusted_task_nullable')")

int untrusted_to_trusted(void *ctx)

{

	return subprog_untrusted2(bpf_get_current_task_btf());

}



char _license[] SEC("license") = "GPL";